#include <stdio.h>

#define ROWS 3
#define COLS 4

int sum2(int rows, int cols, int arr[rows][cols]);

int main(void)
{
    int i, j;
    int rs = 3;
    int cs = 10;

    int junk[ROWS][COLS] = 
    {
        { 2, 4, 6, 8 },
        { 3, 5, 7, 9 },
        { 12, 10, 8, 6}
    };

    int morejunk[ROWS - 1][COLS + 2] = 
    {
        { 20, 30, 40, 50, 60, 70 },
        { 5, 6, 7, 8, 9, 10 }
    };

    int varr[rs][cs];
    for (i = 0; i < rs; i++)
        for (j = 0; j < cs; j++)
            varr[i][j] = i * j + j;
    
    printf("3x4 array\n");
    printf("Sum of all elements = %d\n", sum2(ROWS, COLS, junk));

    printf("2x6 array\n");
    printf("Sum of all elements = %d\n", sum2(ROWS - 1, COLS + 2, morejunk));

    printf("3x10 VLA\n");
    printf("Sum of all elements = %d\n", sum2(rs, cs, varr));

    return 0;
}


int sum2(int rows, int cols, int arr[rows][cols])
{
    int total = 0;
    int r, c;

    for (r = 0; r < rows; r++)
        for (c = 0; c < cols; c++)
            total += arr[r][c];

    return total;
}